Herring are small, silvery, schooling fish found in vast numbers across the world’s oceans. These abundant fish belong to the family Clupeidae, which encompasses around 200 species. They inhabit shallow, temperate waters of the North Pacific and North Atlantic Oceans, including the Baltic Sea, and extend off the west coast of South America.
Physical Traits and Ocean Homes
Herring have streamlined, elongated bodies, typically ranging from 6 to 12 inches in length, though some Atlantic herring can reach up to 18 inches and weigh about 1.5 pounds. Their scales are iridescent silvery, with a bluish or greenish back. This coloration, known as countershading, helps them camouflage from predators by blending into their environment. They possess a single, soft dorsal fin without spines, a small head with a protruding lower jaw, and lack a lateral line.
Herring are pelagic fish, meaning they inhabit the open sea, often beyond the low tide mark. They are commonly found in large schools near fishing banks and coastal areas, living from 2 to 400 meters below the surface. Their preferred habitats include the cold and temperate waters of the North Atlantic, such as the Gulf of Maine, North Sea, and Baltic Sea, and the North Pacific, stretching from Baja California north to Alaska and the Bering Sea.
A Vital Link in Marine Food Webs
Herring hold a significant ecological position as “forage fish,” serving as a conduit for energy transfer within marine ecosystems. They primarily feed on phytoplankton, and as they mature, they expand their diet to include zooplankton, such as copepods, arrow worms, pelagic amphipods, mysids, and krill. During daylight hours, herring often remain in deeper waters, ascending to the surface at night to feed by filtering plankton through their gills.
These small fish are a primary food source for a diverse array of marine predators. Larger fish like cod, tuna, salmon (including Chinook and Coho), and Pacific hake rely on herring for sustenance. Marine mammals, such as whales (including humpback and gray whales), seals, and sea lions, also consume herring. Seabirds, including gulls and surf scoters, are additional predators that depend on herring.
Herring’s role as a keystone species means their abundance directly influences the health and stability of many marine populations. Their ability to convert high-energy plankton into consumable food energy for larger predators underscores their position in supporting entire ecosystems. Fluctuations in herring populations can have cascading effects throughout the food web, impacting species that depend on them for survival.
Herring’s Importance to Humans
Herring have held historical and ongoing significance for human societies globally, often referred to as “silver of the sea” in Europe due to their commercial importance. They have been a staple food source for at least 3000 BC. Commercially, herring are harvested for their flesh and eggs, with the Atlantic herring alone accounting for over half of the world’s commercial capture of herrings.
Herring are consumed in numerous ways, reflecting diverse culinary traditions across different regions. They are often eaten fresh, but also commonly salted, smoked (as kippers), pickled, fermented, or canned. For instance, raw herring with raw onion is a delicacy in the Netherlands, while fermented herring (surströmming) is a traditional food in Sweden. In the Philippines, dried herring is a common breakfast item.
Beyond direct consumption, herring are also processed into other products, including fishmeal and fish oil. A 100-gram serving of raw Atlantic herring provides 158 calories and is a rich source of omega-3 fatty acids, vitamin B12 (570% Daily Value), niacin, vitamin B6, vitamin D, and phosphorus. The economic impact of herring fisheries is substantial, supporting fishing communities and contributing to national economies worldwide.
Life Cycle and Spawning Habits
The reproductive biology of herring involves mass spawning events, typically occurring in coastal waters. While some populations spawn throughout the year, autumn is a dominant spawning season for North Sea herring, with specific populations spawning from August to January in locations like the Scottish and Shetland coasts, the Central North Sea, and the English Channel. Pacific herring generally spawn in the spring, with timing varying by latitude, from mid-March in southeastern Alaska to May and June in the Bering Sea.
Adult herring migrate from the open ocean to sheltered bays and estuaries for spawning, often congregating in large shoals. Females deposit their adhesive eggs on submerged vegetation such as seaweed, eelgrass, or rocky bottoms. A single female can lay between 20,000 and 40,000 eggs. Males then release milt into the water, fertilizing the eggs.
Eggs typically incubate for 10 to 30 days, with about three weeks being common in the North Sea, depending on water temperature. Upon hatching, larvae remain in shallow, nearshore waters to feed and grow. After two to three months, they transform into juveniles, forming schools in bays and inlets before migrating to deeper offshore waters for two to three years. Herring reach sexual maturity around 3 or 4 years of age, with lifespans varying from 8 years in Southeast Alaska to up to 20 years in the cold waters of the Bering Sea.